Two-in-one stringed electronic instrument with string pickup and tone generator



Nov. 10, 1970 R. A. JOHNSON 3,539,699 Two-IN-ONE-STRINGED ELECTRONICINSTRUMENT WITH STRING' PICKUP AND TONE GENERATOR Filed Jan. 26, 1967 @igg afa. H32

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4,/ 4,7 ardJ//ffe United States Patent Ofce 3,539,699 Patented Nov. 10,1970 3,539,699 TWO-IN-ONE STRIN GED ELECTRONIC INSTRU- MENT WITH STRINGPICKUP AND TONE GENERATOR Richard A. Johnson, 1708 N. Quesada St.,Arlington, Va. 22205 Filed Jan. 26, 1967, Ser. No. 611,930 Int. Cl. G10d5 00; G10h 1/00, 5/04 U.S. Cl. 84--1.16 5 Claims ABSTRACT F THEDISCLOSURE A stringed instrument such as a guitar which utilizes anelectronic amplifier coupled to not only reproduce the tones introducedin the strings via a pickup but also selected additional supplementaltones electronically generated. Thus, a fretboard provides electricalswitches selectively positioned for individual selection or concurrentselection while fingering a string for thereby selecting supplementalchords or organ-like tones while the instrument is otherwiseconventionally played. The neck of the instrument is hollow, containingthe switches and associated electronic parts, which are in the form of aprinted circuit board having communication with the switches andestablishing precisely determined resistances from a single resistivestrip by means of a fine tuning slide for each switch. To preventwarping of the hollow neck under tension of taut strings, they arestretched over the end of the neck and back on an opposite side to haveboth ends aiiixed to the instrument body, thereby balancing the forcestending to bow the neck portion.

This invention relates to an electronic string instrument and, moreparticularly, it relates to an electrically supplemented stringinstrument which selectively produces auxiliary tones from an electronictone generator.

While electronic guitars have been known having both electronicamplified string vibrations and supplemental tones (as evidenced by U.S.patent 3,116,357) these instruments have not provided suiiicientdiversity of controls to serve as two different instruments either ofwhich can be played individually or both of which can be played inunison without significally different manual movements.

Thus, it is an objective of this invention to provide improvedelectrically supplemented string instruments in which essentially oneinstrument may be played with tones entirely electronically generatedsuch as in an electronic organ, and wherein this instrument may beplayed individually with or without any relationship to the playing ofthe string instrument itself.

This invention therefore provides for a set of electrical switches inthe fretboard of a guitar which select corresponding tones from anelectronic tone generator. Each switch is located adjacent a string insuch location that the string may be fingered with or without closingthe switch, and the switch may be closed without playing the stringinstrument. Electronic selection devices are located with the switcheswithin a hollow neck which has strings extending over the end and alongboth sides to balance forces tending to bow or twist the neck.

The foregoing and further objects, features, and advantages of theinvention are realized in an embodiment set forth in the followingspecification and its accompanying drawing, wherein:

FIGS. 1 and 2 are respectively elevation and plan views, partly brokenaway, of a guitar constructed in accordance with the invention;

FIG. 3 is an electrical system diagram illustrating the principles ofthe invention;

FIG. 4 is an elevation view in section of a portion of the guitarneck-fretboard arrangement; and

FIG. 5 is a plan view of printed circuit boards located within theguitar neck.

Now with reference to FIGS. 1 and 2, the guitar ernbodiment illustratedhas a body portion 6 and a hollow neck portion 7 with a fretboard 8exhibiting frets 9 on the upper side and having strings 8a stretchedaround the terminal end 10 and indented rollers 10a to extend on theunderside 11 and terminate in tension pegs 12 on the bottom of the bodyportion, which provides balanced stresses thereby eliminating any needfor a steel brace rod and providing rigidity in the greater capacityhollow neck without tendency to bow or bend.

Electronic parts are located within the hollow neck portion 7 as show-non printed circuit board 15 for example and include a set of electricalswitches 16, 16', etc. each switch of which is adjacent a string at afret position so that it may be selectively operated by a fingertipeither simultaneously with a fingering of the string or individuallywithout affecting the adjacent string. Also individually pickuptransducers 20' for each string are located within the hollow body 6.Electrical connections may be made from the guitar body to a singleamplifier system from cable 24 necessitating only two leads 25, 26 plusground lead 27.

As shown in FIG. 3, a typical electronic system provides a single audioamplifier 30 into which signals from all the strings may be introducedvia lead 25 from mixing resistors 31 and corresponding transducers 20. Atone generator such as resistance controlled oscillator 33y is alsoconnected to the amplifier via mixing resistor 32.

In oscillator 33 the frequency adjustment comprises a variable resistor34 which is selectively adjusted by choice of an appropriate selectionswitch 16, etc. to choose a tone simulating an organ or a chord forexample. It is to berecognized that the mixing and frequency selectiontechniques need not be exactly those shown to comply with the spirit andscope of this invention, and that various oscillators or tone devicesmay be used for selection by the electrical switches 16. However, aversatile and simple combination is provided by the single oscillator 33provided with a single variable resistor 34, particularly whenconstructed in the manner hereinafter taught in connection with theviews of FIGS. 4 and 5.

Thus, under fretboard `8 is the hollow cavity of neck 7 from whichswitch buttons 16 protrude adjacent strings r8a in the vicinity of frets9. This button is spring biased by spring 40` electrically soldered togrounding wire 27 and is fashioned to contact a protuberance 41 at afixed position on a set of electrical conductor segments 42 disposed onthe upper side of printed circuit insulator board 15. If desired,several rows of such conductors may be disposed in connection with theseveral instrument strings to communicate with either a single resistor34 in oscillator circuit 33 or with separate similar individualresistors in a plurality of tone generators.

Disposed on the bottom of the board is a long strip 45 of resistancemedium comprising resistor 34. A variable resistance coupling is madefrom each push button switch 16 to a particular line tuned position onresistor 34 by means of a U-shaped bracket or strap 46 indented at `47to make conductive Contact on opposite sides of the printed circuitboard 15 respectively to the resistive strip 45 and one of theconductive portions 42. Thus, the fine tuning strap `46 can be adjustedto choose a resistance within the limits defined by the length of therespective conductive portion 42.

It is seen therefore that simple and effective equipment is afforded bythis invention to provide an improved string instrument which operateseither to produce solos on .means single musician. Having thereforeprovided an improved instrument, I claim as my invention those featuresdescribedin 4the appendedclaims as representative'ofithe neckextendingfrom said body with a, fretboard thereon for lingering thestrings at a set of fret positions, a set of manually. operablevelectrical switches `placed adjacent [.twq diiferentinstrumentsorduets.,by operationvofa Vprisingl in combination, a body containing aplurality of vvibrating strings for producing different musical tones, a

,the strings and frets in saidneck for selective operation independentlywithirespect to. the iingering of a string yat an adjacent fret,electronic amplifier means, electrical signal generating means forreproducing tones from each of the vibrating strings, an auxiliary tonegenerator, means 'coupled with the switches to establish different tonesin said generator, and meansfor independently and selec- `tively mixingthe signals from said generating means and said tone generator forreproduction in said amplifier 2. An instrument as defined in claim 1wherein said i f 3. An instrumentA as defined. in claim `1 wherein said:neck is a hollow shell into which said switches protrude 4and said tonegenerator is responsive toa change in resistance to change tones,including an electronic circuit assembly contained within said neckincluding means selecting a series of different resistances in responseto operation of said switches in said generator and means coupling theresistances to said generator to change tones thereby comprising saidmeans to establish different tones,

said electronic circuit assembly comprises a .printed circuit boardhaving on one side a long strip of material of high resistivity tocomprise the resistance changing the tone of said generator and havingon the other side a set of conductors extending along only a limitedportion of said long strip, means coupling said switches respectively toone of said set of conductors, and adjustable conducting means mov ablealong the conductor and strip to thereby select a particular length ofsaid strip establishing a resistance value corresponding to a finelytuned tone in said generator.

4. A string instrument having a body and a hollow neck portion mountedthereto comprising strings aliixed to and extending from said body alongsaid neck portion to one side and back on the opposite side to a furtheralixed position on the body to thereby balance stresses in the neckproduced by said strings.

5. An instrument as defined in claim 4 whereinindented rollers areprovided at the terminal end of the neck to receive the strings and pegsfor adjusting the tension of said strings are located on the undersideof said body.

References Cited UNITED sTATEs PATENTS 557,277 .2i/1896 Kelly et a1.:s4- 267 586,032 7/1897 Hartman 84-293 3,196,729 7/1965 Bums et a1. 84-171 3,205,294 9/1965 Maynard 84-l.1l 3,223,771 12/1965 Hopping :s4-1.263,116,357 12/1963 Krebs 84 1.16

WARREN E. RAY, Primary Examiner Us. c1. XR. :a4-293, 297

